Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757754AbZISCak (ORCPT ); Fri, 18 Sep 2009 22:30:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757612AbZISCaj (ORCPT ); Fri, 18 Sep 2009 22:30:39 -0400 Received: from mga02.intel.com ([134.134.136.20]:14340 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757206AbZISCai (ORCPT ); Fri, 18 Sep 2009 22:30:38 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.44,412,1249282800"; d="scan'208";a="449834665" Subject: Re: [patch] x86, apic: use logical flat on intel with <= 8 logical cpus From: Suresh Siddha Reply-To: Suresh Siddha To: Daniel Walker Cc: "tglx@linutronix.de" , "hpa@zytor.com" , "mingo@elte.hu" , "yinghai@kernel.org" , "linux-kernel@vger.kernel.org" In-Reply-To: <1253326790.6699.38.camel@desktop> References: <1253325936.3948.720.camel@sbs-t61.sc.intel.com> <1253326790.6699.38.camel@desktop> Content-Type: text/plain Organization: Intel Corp Date: Fri, 18 Sep 2009 19:29:59 -0700 Message-Id: <1253327399.3948.747.camel@sbs-t61.sc.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3577 Lines: 110 On Fri, 2009-09-18 at 19:19 -0700, Daniel Walker wrote: > There are a couple of checkpatch issues in this patch .. Could you run > it through and fix the errors that show up.. One is that you need 1 less > tab for the code inside the switch statement .. You have another switch > statement in apic.c that needs similar attention . Oops. Here it is. Thanks! --- From: Suresh Siddha Subject: x86, apic: use logical flat on intel with <= 8 logical cpus On Intel platforms, we can use logical flat mode if there are <= 8 logical cpu's (irrespective of physical apic id values). This will enable simplified and efficient IPI and device interrupt routing on such platforms. Fix the relevant comments while we are at it. We can clean up default_setup_apic_routing() by using apic->probe() but that is a different item. Signed-off-by: Suresh Siddha --- diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index a34601f..e3654ec 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -62,7 +62,7 @@ unsigned int boot_cpu_physical_apicid = -1U; /* * The highest APIC ID seen during enumeration. * - * This determines the messaging protocol we can use: if all APIC IDs + * On AMD, this determines the messaging protocol we can use: if all APIC IDs * are in the 0 ... 7 range, then we can use logical addressing which * has some performance advantages (better broadcasting). * @@ -1917,24 +1917,14 @@ void __cpuinit generic_processor_info(int apicid, int version) max_physical_apicid = apicid; #ifdef CONFIG_X86_32 - /* - * Would be preferable to switch to bigsmp when CONFIG_HOTPLUG_CPU=y - * but we need to work other dependencies like SMP_SUSPEND etc - * before this can be done without some confusion. - * if (CPU_HOTPLUG_ENABLED || num_processors > 8) - * - Ashok Raj - */ - if (max_physical_apicid >= 8) { - switch (boot_cpu_data.x86_vendor) { - case X86_VENDOR_INTEL: - if (!APIC_XAPIC(version)) { - def_to_bigsmp = 0; - break; - } - /* If P4 and above fall through */ - case X86_VENDOR_AMD: + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_INTEL: + if (num_processors > 8) + def_to_bigsmp = 1; + break; + case X86_VENDOR_AMD: + if (max_physical_apicid >= 8) def_to_bigsmp = 1; - } } #endif diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c index 65edc18..41e8509 100644 --- a/arch/x86/kernel/apic/probe_64.c +++ b/arch/x86/kernel/apic/probe_64.c @@ -64,16 +64,23 @@ void __init default_setup_apic_routing(void) apic = &apic_x2apic_phys; else apic = &apic_x2apic_cluster; - printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); } #endif if (apic == &apic_flat) { - if (max_physical_apicid >= 8) - apic = &apic_physflat; - printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_INTEL: + if (num_processors > 8) + apic = &apic_physflat; + break; + case X86_VENDOR_AMD: + if (max_physical_apicid >= 8) + apic = &apic_physflat; + } } + printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); + if (is_vsmp_box()) { /* need to update phys_pkg_id */ apic->phys_pkg_id = apicid_phys_pkg_id; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/